Sunday, April 25, 2021
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
SUNDAY, APRIL 25, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0448E
SUNSET: 1837E
RAINY IN THE MORNING WITH MOSTLY CLOUDY SKIES
IN THE AFTERNOON….
Today was very different in comparison to yesterday, as
we had 0.20 inches of rainfall after 7 A.M. The rain
ended by noontime, and visibility rose to 20 miles by
the 1 P.M. observation. Pressure is on a slow decline,
keeping most of the Boston area cloudy. Wind is on the
lighter side, with an average speed of 10 mph and only
20 mph for the max gust. Wind direction switched from
south to east as the rain came through.
We continue to hold our “Climb for Climate” event up here.
Our challenge to our Greater Boston community is to climb
up Great Blue Hill to the Observatory and be counted as a
supporter of Mother Earth. We have logged more than 600
people since the start 3 days ago. The weather for today
looks less than favorable, but it seems to be improving.
We continue to provide rooftop tours until 4 P.M.
The high so far today is 52F, this is 7 degrees below the
normal high of 59F. The low since midnight is 46F, which
is 5 degrees above the daily normal low of 41F.
Today’s Observations:
7 A.M.
Weather: Overcast altostratus
Temperature: 47F; Dew Point: 42F; Relative Humidity: 81%
Wind: S at 12 kts
Sea-level pressure: 29.79 in Hg, rising, then more slowly
Visibility: 10 miles, thin fog
6-hr Max temp: 52F
6-hr Min temp: 47F
24-hr Precip: Trace
24-hr Snow: 0.0 ins.
Snow Depth: 0.0 ins.
BHO SA 1155 90 OVC 10R- 091/47/42/1912/979/ R-CTD THN F ALQDS/
8/02/ 70000 53004 10052 20047
10 A.M.
Weather: Overcast stratus
Temperature: 48F; Dew Point: 47F; Relative Humidity: 95%
Wind: E @ 7 kts
Sea-level pressure: 29.80 in Hg; rising steadily
Visibility: 1 mile, fog
3-hr Precip: 0.17 ins.
3-hr Snow: 0.00 ins.
BHO SA 1455 50 OVC 1R-F 093/48/47/0807/980/ R-CTD/ 8/6// 6017/
53002
1 P.M.
Weather: Overcast stratocumulus, very light rain
Temperature: 50F, Dew point: 46F; Relative Humidity: 84%
Wind: E @ 7 kts
Sea-level pressure: 29.74 in Hg; falling, then falling more slowly
Visibility: 20 miles, thin fog
6-hr Max temp: 52F
6-hr Min temp: 46F
6-hr Precip: 0.20 ins.
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 50 OVC 20R- 075/50/46/0807/974/ R-CTD PCPN VRY LGT/
8/8// 6020/ 58018 10052 20046
SUMMARY FOR SATURDAY, APRIL 24, 2021
TEMPERATURE (DEGREES F)
MAX…….70 NORMAL…..59
MIN…….44 NORMAL…..41
MEAN……57 NORMAL…..50
DEPARTURE FROM 30-YEAR (1981-2010) NORMAL…….+7
TOTAL DEPARTURE FOR THE MONTH……………….+32 [+1.1 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………….8 DEPARTURE…….-7
TOTAL HEATING UNITS FOR THE MONTH…………..434 DEPARTURE……-34
TOTAL HEATING UNITS FOR THE SEASON…………5256 DEPARTURE…..-696
TOTAL HEATING UNITS LAST SEASON TO DATE…….5371 DEPARTURE…..-140
PEAK WIND GUST (MPH):
420C/Official…………..33 WNW @ 12:40 P.M.
AEROVANE (south tower)…..37 WNW @ 12:39 P.M
ASOS…………………..34 W @ 1:01 P.M
DAVIS #1……………….36 W @ 12:41 P.M
DAVIS #2 (south tower)…..34 WNW @ 12:40 P.M
RMY……………………35 @ 1:00 P.M
VECTOR…………………39 @ 1:00 P.M
MERLIN…………………34
FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………25 W @ 1:02 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….25 W @ 1:02 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………28 W @ 1:02 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………27 W @ 1:01 P.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..23 WNW @ 1:02 P.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..26 @ 12:57 P.M.
AVERAGE WIND SPEED AND DIRECTION:
CONTACTING/OFFICIAL……12.4 W [298 total miles] ASOS…………………12.5
DAVIS #1……………..12.7 W
DAVIS #2……………..12.7 W
RMY………………….11.8 W
VECTOR……………… 12.3
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….0.00 DEPARTURE….-0.13
ASOS………….0.00
TOTAL PRECIPITATION FOR THE MONTH………….4.01 DEPARTURE….+0.26
ASOS………….3.91
TOTAL PRECIPITATION FOR THE YEAR………….14.18 DEPARTURE….-3.56
ASOS………..14.42
SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HOURS ENDING 7 A.M………..0.0 DEPARTURE…..-0.1
TOTAL SNOWFALL FOR THE MONTH ………………3.6 DEPARTURE…..+0.7
TOTAL SNOWFALL FOR THE SEASON……………..76.2 DEPARTURE….+14.1
PRELIMINARY CLIMATE SUMMARY FOR APRIL CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/PEAK GUST/AERO/RMY GUST
AERO: Aerovane wind recording system gust
RMY: R.M. Young wind gust recording system
TSTM: Thunderstorm day (thunder heard some time during day)
….: Data not yet available, records not finalized
M: Missing data
04/01 56/30/43/+2/0.89/T/000/00 44 NW AERO 51 NW RMY 49
04/02 37/24/31/-10/0.00/0.0/614/80 28 NW AERO 32 NNW RMY 30
04/03 48/23/36/-6/0.00/0.0/755/98 24 NW AERO 25 NW RMY 26
04/04 58/33/46/+4/0.00/0.0/734/95 38 NNW AERO 41 NNW RMY 41
04/05 57/41/49/+6/T/T/031/04 41 NNW AERO 48 NNW RMY 50
04/06 61/40/51/+8/0.00/0.0/412/53 26 NNW AERO 25 NNW RMY 31
04/07 57/41/49/+6/0.00/0.0/391/50 23 ENE AERO 21 ENE RMY 22
04/08 59/43/51/+7/0.00/0.0/745/95 22 ENE AERO 22 ENE RMY 24
04/09 69/42/56/+12/0.00/0.0/707/90 24 S AERO M M RMY 26
04/10 75/43/59/+14/0.00/0.0/576/73 26 SSW AERO 28 SSW RMY 30
04/11 53/40/47/+2/T/0.0/000/00 33 ENE AERO 33 ENE RMY 34
04/12 46/37/42/-3/0.05/0.0/000/00 36 ENE AERO 37 ENE RMY 41
04/13 56/37/47/+1/T/0.0/…/.. 31 NE AERO 30 NE RMY 33
04/14 56/42/49/+3/0.00/0.0/…/.. 22 ESE AERO 23 ESE RMY 22
04/15 51/37/44/-3/0.30/0.0/…/.. 26 ESE AERO 25 ESE RMY 28
04/16 39/31/35/-12/2.22/3.6/…/.. 48 NNW AERO 58 NNW RMY 58
04/17 45/34/40/-7/0.07/T/…/.. 27 NNW AERO 30 NNW RMY 29
04/18 60/38/49/+1/0.00/0.0/…/.. 28 NW AERO 28 NW RMY 31
04/19 66/44/55/+7/T/0.0/…/.. 22 SSW AERO 25 SSW RMY 28
04/20 72/45/59/+10/0.00/0.0/…/.. 38 SW AERO 37 WSW RMY 40
04/21 68/32/50/+1/0.48/…/…/.. 45 S AERO 51 S RMY 51
04/22 44/28/36/-13/T/T/…/.. 54 W AERO 55 W RMY 59
04/23 58/32/45/-5/0.00/0.0/…/.. 47 W AERO 48 W RMY 52
04/24 70/44/57/+7/0.00/0.0/…/.. 33 WNW AERO 37 WNW RMY 55
04/25 The low since midnight is 47F, the daily normal low is 41F
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated)
RECORDS FOR APRIL 25
HIGH 83 IN 2009
LOW 24 IN 1892
PRECIP 1.38 IN. IN 1901
SNOWFALL 0.7 IN. IN 2002
PEAK GUST 66 MPH SE IN 1968
RECORDS FOR APRIL 26
HIGH 88 IN 2009
LOW 23 IN 1919
PRECIP 1.64 IN. IN 1931
SNOWFALL 1.0 IN. IN 2000
PEAK GUST 53 MPH SSW IN 1996
TODAY’S REPORT PREPARED BY: Benjamin Turner
